DSL Safety Net

Upgrading the CBOS on Cisco 675/678

Use one of the following two procedures to upgrade the CBOS image in your Cisco 675 or 678 DSL modem. These procedures require that you first connect your computer serial port to the management port of the Cisco, and you have a serial terminal emulation program that supports the xmodem file transfer protocol. 

You enter the commands shown in bold type face.  The notation "cr" is a carriage return or Enter key.

Upgrading from a working CBOS

Step 1: Download the CBOS binary image from the netrack.net web site to the computer connected to your Cisco modem's management port. The latest CBOS is here. Expand the archive so that you have a .bin file and the release notes. Contact NeTrack if you are in doubt as to which image to download.

Step 2: Open an xmodem-compatible terminal emulation program such as Hyperterminal (hypertrm.exe). Ensure your terminal settings are:

38400 bits per second
No parity
8-data bits
1-stop bit
No flow control

Step 3: Connect to the Cisco modem by specifying a direct (not dialup) connection directly to the serial port you are using (on Windows, Direct to COM1 or Direct to COM2). Log in to the Cisco modem

Step 4: Enter priviledged mode:

Step 5: Set the Cisco modem to receive the new CBOS image file:

Step 6: In the terminal emulation program menus, select the menu item to send a file using the xmodem protocol. It should then bring up a file browser. Use the file browser to select the .bin file you downloaded in Step 1. The transfer should take approximately 15 minutes.

Step 7: The Cisco modem should automatically reboot.  If it does not, enter a reboot command:

Upgrading from a non-working CBOS

It is possible for the CBOS image to become corrupted and cause the modem to not boot fully. In such a case, you will not have a "CBOS>" prompt.

Step 1: Download the CBOS binary image from the netrack.net web site to the computer connected your Cisco modem's management port. The latest CBOS is here. Expand the archive so that you have a .bin file and the release notes. Contact NeTrack if you are in doubt as to which image to download.

Step 2: Open an xmodem-compatible terminal emulation program such as Hyperterminal (hypertrm.exe). Ensure your terminal settings are:

38400 bits per second
No parity
8-data bits
1-stop bit
No flow control

Step 3: Connect to the Cisco modem and erase the existing contents of the firmware:

Step 4: Transfer the new CBOS image to the Cisco modem:

Step 5: Set the address for the new CBOS image.  Note that the last field on this command (ce000) is the number of bytes shown as downloaded in the previous step.  Leading zeros do not need to be entered. Enter the number of bytes actually shown on your Cisco modem as downloaded, not the number shown in this example.

Step 6: Report the Cisco modem: